In spite of recent development in fixation technique we still have lots of complication including avascular necrosis of femoral head. For many years, orthopaedic surgeon have been searching for a simple, safe, accurate and reliable clinical test to asses the vascular status of the femoral head. In early detection of viability of the femoral head, nothing is more certain than bone scan at the moment. Bone scan can detect or predict the viability of the femoral head. Subramanian and McAfee introduced ^99mTc-Sn-polyphosphate as a bone seeking agents. We applied serial bone scan in 19 cases of femur neck fractures from 1982 to 1985 at the department of orthopaedic surgery, National Medical Center. The results were as follows; 1. The uptake ratio of displaced and undisplaced group based on preoperative radiography was 1.ZO, 1.46, 1.52, 1.55, and 0.63, 1.23, 1.81, 1.58 in average in postoperative bone scan interval 1–2 wks, 3 months, 6 months, 12 months. The bone scan uptake ratio was lower in the former than the latter, but after 3 months, there was no remarkable difference between them. 2. At the time of 1 to 2 weeks, 3 months, 6 months and 12 months, uneventful group was 0.74, 1.27, 1.72, 1.62 and avascular necrosis group 0.13, 0.18, 0.30, 0.67 in the uptake ratio. In 2 cases of avascular necrosis, the uptake ratio was markedly decreased. 3. There was no difference between the group operated within 48 hour after injury and the group delayed later.